I have a Heiland 3 cell flash that seems to work just fine... however...

The red button sets off the flash and the rear plug sets off the flash when I plug in my remote fire button. However, neither one of the side plugs seem to work. I plug in the cable and attach it to my synch plunger on my shutter and nothing happens.
The cord seems to work fine and I have another flash tower identical to the first and they both seem to have the same problem.
At first I thought it was the synch but I don't think that is the case. If I plug the cord into either of the side slots and try to set it off by simply cross shorting the synch plug end, it still does not go off. The cord sets off the rear plug when I cross it... so I do not think it is the cord.

I assume you are trying to trip an electromagnetic shutter tripper (solenoid). You should use a volt meter to see if you have voltage to the outlet AND the solenoid end of your cord when you press the button. My guess is that you have a bad solenoid.

plug the cord into one of the side slots and into the solenoid (synch plunger)

Cock the shutter

Hit the flash button on the back of the flash.

Did it trip the shutter?

Did it TRY to trip the shutter?

In normal operation, pushing the flash button on the battery case closes two circuits. One to the flash bulb, and one to the solenoid. There is (supposed) to be enough slop in the solenoid linkage to delay the shutter opening until the bulb reaches its peak output.

The solenoid works because if I trip it using a battery and two wires it snaps the shutter perfect. The cord works because I can plug the cord to the solenoid and touch the other end to a battery and, bang, it trips no problem.
The push button on the flash tube works fine because if I put a flash bulb in in and hit the button, it pops...

So that narrows it down to the plugs. I have checked all of the connections inside the system by taking it apart and I do not see any problems.
Any thoughts?

As it turned out, there was a fiber washer on one of the screws when there should have been a brass one. It was interupting the current and cutting off the side plugs. Seems to work fine now. Thanks to everyone for giving me a hand, happy shutterbugging!!

It is a 1942 4x5 US Army Signal Corps Speed Graphic, note all of the hardware is painted black.
It is in perfect working order now, the flash was the last wrinkle to work out. I fully restored this camera from the ground up as it was just a shell when I found it.
A little cleaning, part restoration and leather repair, and now she is ready for combat!

For a long time I used a Baby Speed Graphic for my combat photography but now this is my primary camera. Sure is heavier than my baby that is for sure!

Glen;
I know it's a Heiland '70'bracket, as I have the left-side version on the camera, along with a couple of sets of mounting rings.
I also have the earlier Heiland bracket with the slotted key lower ring, the later Heiland thumb-lever bracket. and the later still thumb screw bracket. What I don't have is that exact bracket.
Top (who might as well call it quits and mount King Sol 1/4"x20 shoes on everything).

What I need is a Graflex flash for this camera, that is the period correct item that should be attached to it. But since all of the St*rW*ars a**holes take them all I have not been able to track one down for a reasonable price.
If you want this flash bracket I am no longer using it, as far as I can tell it is not period for wartime use. Know of one for the Heiland that is period and do you have a spare?

AFAIK, the Heiland '70' brackets are wartime.
There is a picture in the forward of 'Life Goes to War' of Frank Scherschel with an Anny mounting a Heiland gun with the right-angle head for #5 bulbs on the left side, and it's either on a '70' bracket or the key-slot lower bracket. My '40/41 Anny came with one of these installed.
My '45 Military contract Anny came with a Heiland/Sol gun in the thumbscrew bracket that mounts on the rail of the Kalart RF.
Graflex was a latecomer to the business of flashguns, and a check of period pictures shows that there were more Heiland/Sol, King Sol, Mendelsohn and Kalart flashguns in service than Graflex pre-war and wartime. Post-war, Graflites ruled until the advent of strobes.
If anyone out there can give dates of introduction for any of this gear I wouldn't mind seeing it.
Top
(who is really thinking of going back to a pair of Contax II and a Rolleiflex Automat I).

The first ones (production quantity unkown) have parallel lines around the ports and an open "morse code key" type rear button.

The speed lines were dropped at the same time the more common closed rear red button was implemented. When this happened is a mystery. I've seen drawings showing the closed button as early as June of 1940.

In 1945 the bottom end of the 2 and 3 cells chambers were changed to reflect the new corporate name (Graflex inc) and that they had patent numbers now.

In 1950 the Graflite flash was introduced, but will say G R A F L E X around the middle of the battery case.

Notice this means the early Pacemakers would have used the older Graflex flash.

Oh an not that I'm being picky, but I suspect the Graphex (X) shutter will say "Graflex, Inc" on it, making it post '45. I know what got into the field and what was written in manuals are usually far different, but I haven't seen any reference to an X sync only shutter being made until post war.